For saving of resources, in some case, image formation is performed using erasable developing materials. As the erasable developing materials, there are toner, ink, and the like erased by heat. Recording media on which images are formed with such erasable developing materials are reused after being heated by an erasing apparatus to have the images erased from the recording media.
However, in some case, plural used recording media inserted into the erasing apparatus are bound by a clip or a stapler. When the plural bound recording media are conveyed, the recording media cause a jam halfway in a recording medium conveying mechanism and cause a failure of the erasing apparatus.
Concerning this problem, a technique for detecting double feed with a double-feed detection sensor is proposed. However, in some case, double feed cannot be detected by the double-feed detection sensor. Therefore, there is a demand for a recording medium sorting apparatus, an erasing apparatus, and a recording medium sorting method that efficiently sort recording media that are likely to cause a jam.